Digital microfluidic device, microfluidic apparatus, lab-on-a-chip device, digital microfluidic method, and method of fabricating digital microfluidic device

Abstract

A digital microfluidic device includes a thin film transistor driving substrate. The thin film transistor driving substrate includes a first base substrate; a plurality of sample actuating units; a plurality of sample position detecting units; a dielectric insulating layer on a side of the plurality of sample actuating units and the plurality of sample position detecting units distal to the first base substrate; and a first hydrophobic layer on a side of the dielectric insulating layer distal to the first base substrate. Each of the plurality of sample actuating units includes a first electrode configured to drive transportation of a liquid droplet on the digital microfluidic device. Each of the plurality of sample position detecting units includes a photosensor configured to detect presence or absence of the liquid droplet on a position corresponding to the photosensor.

What is claimed is: 
     
       1. A digital microfluidic device, comprising a thin film transistor driving substrate;
 wherein the thin film transistor driving substrate comprises: 
 a first base substrate; 
 a plurality of sample actuating units; 
 a plurality of sample position detecting units; 
 a dielectric insulating layer on a side of the plurality of sample actuating units and the plurality of sample position detecting units distal to the first base substrate; and 
 a first hydrophobic layer on a side of the dielectric insulating layer distal to the first base substrate; 
 wherein each of the plurality of sample actuating units comprises: 
 a first thin film transistor on the first base substrate, and comprising a first gate electrode, a first source electrode, and a first drain electrode; and 
 a first electrode electrically connected to the first drain electrode and configured to drive transportation of a liquid droplet on the digital microfluidic device; 
 wherein each of the plurality of sample position detecting units comprises: 
 a second thin film transistor on the first base substrate, and comprising a second gate electrode, a second source electrode, and a second drain electrode; and 
 a photosensor electrically connected to the second source electrode, and configured to detect presence or absence of the liquid droplet on a position corresponding to the photosensor. 
 
     
     
       2. The digital microfluidic device of  claim 1 , further comprising:
 a gate line electrically connected to the first gate electrode and the second gate electrode, and configured to provide a gate scanning signal to turn on the first thin film transistor and the second thin film transistor, 
 a first electrode driving signal line electrically connected to the first source electrode, and configured to provide a driving signal to the first electrode when the first thin film transistor is turned on; and 
 a read line electrically connected to the second drain electrode, and configured to transmitting signals detected by the photosensor. 
 
     
     
       3. The digital microfluidic device of any one of  claims 1  to  2 , further comprising:
 a common electrode electrically connected to the photosensor; and 
 a common electrode signal line configured to be provided with a common voltage signal to the common electrode; 
 wherein the photosensor comprises: 
 a first polarity region electrically connected to the common electrode; 
 a second polarity region electrically connected to the second source electrode; and 
 a diode junction electrically connecting the first polarity region and the second polarity region. 
 
     
     
       4. The digital microfluidic device of  claim 3 , further comprising a contact electrode electrically connecting the second polarity region to the second source electrode;
 wherein the contact electrode and the second source electrode are in a same layer and comprise a same material. 
 
     
     
       5. The digital microfluidic device of any one of  claims 1  to  4 , further comprising a first insulating layer on a side of the second source electrode distal to the first base substrate;
 wherein a lateral side of the photosensor adjacent to the second source electrode is spaced apart from the second source electrode by the first insulating layer. 
 
     
     
       6. The digital microfluidic device of  claim 5 , wherein the first insulating layer is on a side of the first source electrode, the first drain electrode, the second source electrode, and the second drain electrode distal to the first base substrate;
 the thin film transistor driving substrate comprises a first via extending through the first insulating layer; and 
 the photosensor is electrically connected to the second source electrode through the first via. 
 
     
     
       7. The digital microfluidic device of  claim 6 , further comprising:
 a common electrode electrically connected to the photosensor, and on a side of the photosensor distal to the first base substrate; 
 a second insulating layer on a side of the common electrode and the photosensor distal to the first base substrate; 
 a common electrode signal line configured to be provided with a common voltage signal to the common electrode, and on a side of the second insulating layer distal to the first base substrate; 
 wherein the thin film transistor driving substrate comprises a second via extending through the second insulating layer; and 
 the common electrode signal line is electrically connected to the common electrode through the second via. 
 
     
     
       8. The digital microfluidic device of  claim 7 , further comprising:
 a third insulating layer on a side of the common electrode signal line distal to the first base substrate; 
 wherein the first electrode is on a side of the third insulating layer distal to the first base substrate, and on a side of the dielectric insulating layer facing the first base substrate; 
 the thin film transistor driving substrate comprises a third via extending through the third insulating layer and the second insulating layer; and 
 the first electrode is electrically connected to the first drain electrode through the third via. 
 
     
     
       9. The digital microfluidic device of any one of  claims 1  to  8 , further comprising a counter substrate spaced apart from the thin film transistor driving substrate;
 wherein the counter substrate comprises: 
 a second base substrate; 
 a second electrode on a side of the second base substrate facing the thin film transistor driving substrate; and 
 a second hydrophobic layer on a side of the second electrode facing the thin film transistor driving substrate. 
 
     
     
       10. The digital microfluidic device of any one of  claims 1  to  9 , wherein an orthographic projection of the first electrode on the first base substrate covers an orthographic projection of the photosensor on the first base substrate; and
 the first electrode is a substantially transparent electrode. 
 
     
     
       11. The digital microfluidic device of any one of  claims 1  to  10 , comprising an array of a plurality of sample actuating and position detecting units;
 wherein each of the plurality of sample actuating and position detecting units comprising one of the plurality of sample actuating units and one of the plurality of sample position detecting units; and 
 the first thin film transistor of the one of the plurality of sample actuating units and the thin film second transistor of the one of the plurality of sample position detecting units are electrically connected to a same gate line, and are configured to be turned on simultaneously. 
 
     
     
       12. The digital microfluidic device of  claim 11 , further comprising a plurality of gate lines, a plurality of first electrode driving signal lines, and a plurality of read lines;
 wherein the plurality of gate lines intersect with the plurality of first electrode driving signal lines and the plurality of read lines, thereby forming a plurality of sample actuating and position detecting regions; and 
 the plurality of sample actuating and position detecting units are respectively in the plurality of sample actuating and position detecting regions. 
 
     
     
       13. A microfluidic apparatus, comprising the digital microfluidic device of any one of  claims 1  to  12 ;
 a photo-sensing circuit configured to receive signals detected by the photosensor, and 
 an electrode driving circuit configured to provide a driving signal to the first electrode. 
 
     
     
       14. A lab-on-a-chip device, comprising the digital microfluidic device of any one of  claims 1  to  12 . 
     
     
       15. A digital microfluidic method, comprising selectively transporting a liquid droplet using a digital microfluidic device;
 wherein the digital microfluidic device comprises a thin film transistor driving substrate; 
 wherein the thin film transistor driving substrate comprises: 
 a first base substrate; 
 a plurality of sample actuating units; 
 a plurality of sample position detecting units; 
 a dielectric insulating layer on a side of the plurality of sample actuating units and the plurality of sample position detecting units distal to the first base substrate; and 
 a first hydrophobic layer on a side of the dielectric insulating layer distal to the first base substrate; 
 wherein each of the plurality of sample actuating units comprises: 
 a first base substrate; 
 a first thin film transistor on the first base substrate, and comprising a first gate electrode, a first source electrode, and a first drain electrode; 
 a first electrode electrically connected to the first drain electrode and configured to drive transportation of a liquid droplet on the digital microfluidic device; 
 wherein each of the plurality of sample position detecting units comprises: 
 a second thin film transistor on the first base substrate, and comprising a second gate electrode, a second source electrode, and a second drain electrode; 
 a photosensor electrically connected to the second source electrode, and configured to detect presence or absence of the liquid droplet on a position corresponding to the photosensor; 
 wherein the method comprises: 
 detecting a position of the liquid droplet relative to the plurality of sample position detecting units using the photosensor in each individual one of the plurality of sample position detecting units; and 
 driving transportation of the liquid droplet on the digital microfluidic device based on the position of the liquid droplet relative to the plurality of sample position detecting units. 
 
     
     
       16. The digital microfluidic method of  claim 15 , wherein driving transportation of the liquid droplet comprises:
 determining a present sample actuating and position detecting region in which the liquid droplet is at least partially located and a present sample actuating unit of the plurality of sample actuating units is located; and 
 actuating the first electrode in a next directly adjacent sample actuating unit of the plurality of sample actuating units in a next directly adjacent sample actuating and position detecting region, thereby transporting the liquid droplet along a direction from the present sample actuating unit to the next directly adjacent sample actuating unit. 
 
     
     
       17. The digital microfluidic method of  claim 16 , wherein actuating the first electrode in the next directly adjacent sample actuating unit comprises:
 providing a driving signal to the first source electrode of the first thin film transistor in the next directly adjacent sample actuating unit; and 
 providing a gate scanning signal to turn on the first thin film transistor in the next directly adjacent sample actuating unit, thereby allowing the driving signal to be provided to the first electrode in the next directly adjacent sample actuating unit. 
 
     
     
       18. The digital microfluidic method of any one of  claims 15  to  17 , wherein detecting the position of the liquid droplet relative to the plurality of sample position detecting units comprises:
 providing a gate scanning signal to turn on the second thin film transistor; 
 transmitting a photo-sensing signal detected by the photosensor, and 
 comparing the photo-sensing signal with a reference signal, thereby determining presence or absence of the liquid droplet at the position corresponding to the photosensor. 
 
     
     
       19. The digital microfluidic method of any one of  claims 15  to  18 , wherein the digital microfluidic device comprises:
 an array of a plurality of sample actuating and position detecting units arranged in rows and columns; 
 a plurality of gate lines; 
 a plurality of first electrode driving signal lines; and 
 a plurality of read lines; 
 wherein each of the plurality of sample actuating and position detecting units comprising one of the plurality of sample actuating units and one of the plurality of sample position detecting units; 
 the plurality of gate lines intersect with the plurality of first electrode driving signal lines and the plurality of read lines, thereby forming a plurality of sample actuating and position detecting regions; and 
 the plurality of sample actuating and position detecting units are respectively in the plurality of sample actuating and position detecting regions; 
 wherein the method comprising providing a plurality of gate scanning signals respectively through the plurality of gate lines to a plurality rows of the plurality of sample actuating and position detecting units respectively; and 
 first thin film transistors and second thin film transistors respectively in the plurality of sample actuating and position detecting units are turned on row by row. 
 
     
     
       20. A method of fabricating a digital microfluidic device, comprising forming a thin film transistor driving substrate;
 wherein forming the thin film transistor driving substrate comprises forming a plurality of sample actuating units and a plurality of sample position detecting units on a first base substrate; 
 forming a dielectric insulating layer on a side of the plurality of sample actuating units and the plurality of sample position detecting units distal to the first base substrate; and 
 forming a first hydrophobic layer on a side of the dielectric insulating layer distal to the first base substrate; 
 wherein forming each of the plurality of sample actuating units comprises: 
 forming a first thin film transistor on the first base substrate, the first thin film transistor formed to comprise a first gate electrode, a first source electrode, and a first drain electrode; and 
 forming a first electrode electrically connected to the first drain electrode and configured to drive transportation of a liquid droplet on the digital microfluidic device; 
 wherein forming each of the plurality of sample position detecting units comprises: 
 forming a second thin film transistor on the first base substrate, the second thin film transistor formed to comprise a second gate electrode, a second source electrode, and a second drain electrode; and 
 forming a photosensor electrically connected to the second source electrode, and configured to detect presence or absence of the liquid droplet on a position corresponding to the photosensor.